Alzheimer's disease (AD) is the leading cause of dementia in the United States and a serious threat to public health. AD patients experience impairments in memory, movement, speaking and comprehension, personality changes and disorientation. The accompanying neuropathological hallmarks are senile plaques comprised of the amyloid-beta (Ab) peptide, neurofibrillary tangles, and neuronal loss within the hippocampus and neocortical areas. Ab has emerged as a key player in the pathogenesis of AD; particularly due to the evidence that genetic mutations in presenilin 1, 2 and amyloid precursor protein, which effectively increase the pro-amyloidogenic Ab1-42, are thought to cause familial AD. Most recently soluble oligomeric forms of Ab (AbOs), as well oligomers of other amyloidogenic proteins, have been implicated as toxic mediators of cognitive deficits and synaptic dysfunction. Our laboratory is interested in developing an immunotherapeutic to clear or neutralize AbOs within the parenchymal space. We seek to deliver to the brain recombinant viral vectors which will express a human single chain fragment variable (scFv) antibody directed against various AbOs with the goal of facilitating clearance and preventing synaptic dysfunction and neuronal toxicity. AIM 1: Develop human scFv antibodies directed against conformational epitopes of AbOs targeting particular oligomeric species recently shown to be correlated with memory deficits. We will screen a human scFv phage display library on different amyloid proteins. The phage library will be panned on aggregated alpha-synuclein, binders amplified, and the enriched phage stock subsequently panned on AbOs. AIM 2: Clone scFv genes into recombinant adeno-associated viral (rAAV) vectors, package into virus and evaluate for its efficacy to express bio-active scFv antibody. AIM 3: Deliver the rAAV scFv into the brains of an AD mouse model by stereotaxic injections into the hippocampi. Evaluate the effects of the expressed scFv by using a behavioral measure, the Barnes maze, as well as histological and biochemical analyses to measure the Ab levels in the brain. Alzheimer's Disease is a neurodegenerative disease currently affecting an estimated 4-5 million Americans with health care costs over $100 billion annually, yet as the baby boomer generation ages this number will more than triple. No matter how costly, a price can not be put on the emotional burden that family and care- givers undertake. We hope our research better elucidates the pathological mechanisms and will be a great step toward developing an effective therapeutic for AD patients. [unreadable] [unreadable] [unreadable]